A splitting device for supercritical fluid chromatograph and mass spectrometer

Abstract

The invention relates to the field of supercritical fluid chromatography and provides a shunting device for combined use of a supercritical fluid chromatograph and a mass spectrometer. The shunting device is simple in structure and can effectively reduce the supercritical carbon dioxide vaporization phenomenon and improve the mass spectrum resolution and accuracy. The device comprises a reagent bottle, a back pressure pump, a first three-way control valve, a second three-way control valve and a stop valve, wherein one inlet end of the first three-way control valve is used for communicating with a sample flow-out pipeline of the chromatograph, and the other inlet end communicates with the reagent bottle through the back pressure pump; one outlet end of the first three-way control valve is connected with an inlet end of the second three-way control valve, the other inlet end of the second three-way control valve is used for being connected with a phase combining manager of the chromatograph, and an outlet end of the second three-way control valve communicates with a sample flow-in pipeline of the mass spectrometer; the stop valve is arranged at the inlet end, connected with the phase combining manager of the chromatograph, of the second three-way control valve and can detect pressure from two sides, and the stop valve is opened when pressure difference occurs.

Description

technical field [0001] The invention relates to the field of supercritical fluid chromatography, in particular to a splitting device used in conjunction with a supercritical fluid chromatography and a mass spectrometer. Background technique [0002] Patent CN2150559Y discloses a supercritical fluid chromatograph, which has a flow splitting device, which is used to divide the liquid in the liquid path into two paths, so as to realize precise flow splitting of the liquid. CN103376293A and CN204116296U disclose a kind of precision shunting device applied in supercritical fluid chromatography system, by shunting device main body, metering rod, replaceable inlet filter, adjustable threaded rod, stepper motor, replaceable outlet liquid core and adjustable The main body of the diverter device is provided with a liquid inlet, a low-speed diversion liquid outlet and a high-speed diversion liquid outlet. The metering rod is driven by the stepping motor to move, and a transitional fit...

AI Technical Summary

Problems solved by technology

[0003] Existing technology can realize split flow, but does not take into account the particularity of the combination of supercritical fluid chromatography and mass spectrometer, and there are still relatively large defects: 1. Supercritical fluid chromatography (SFC) uses supercritical carbon dioxide as the mobile phase, which needs to be maintained at a certain level. The pressure and temperature, and according to the nature of the material components, add a small amount of modifier (generally less than 10%), in the analysis of SFC, because there is a period of time when the mobile phase contains the sample and a time period that does not contain the sample, so The flow rate of the mobile phase changes with time

If the flow rate of the mobile phase changes, the heat of vaporization of carbon dioxide at the outlet of the pressure control valve also changes, and the cooling heat changes accordingly, so the temperature of the fluid at the outlet of the pressure control valve changes, resulting in a flow in the flow path at the back of the valve. The phase is easy to vaporize, and finally the product is precipitated, and it is easy to remain in the pipeline, or even block the pipeline

2. The type of modifier affects mass spectrometry. There are many types of modifiers used in SFC analysis, including not only polar solvents such as methanol, acetonitrile, and isopropanol, but also weak polar solvents such as heptane, n-hexane, Weak polar solvents such as tetrahydrofuran will easily affect the atomization effect, the cone of the mass spectrometer ion source is easily contaminated, and the degree of ionization of the mass spectrometer is affected, resulting in a decrease in the resolution and accuracy of the mass spectrometer. detected, resulting in an error in the analysis result

3. Electrospray ionization source (ESI) is currently the most commonly used ion source for mass spectrometers. It is usually necessary to add ion-pairing reagents such as formic acid, ammonia water, ammonium formate, etc. to improve the ionization effect of compounds and improve the sensitivity of mass spectrometry analysis, especially for low For high-resolution mass spectrometers with flow rates, sometimes ion-pair reagents directly determine the accuracy of the analysis results, and ion-pair reagents often affect the separation effect of supercritical fluid chromatography, so it is not suitable to be added to supercritical fluid chromatography as a modifier in the mobile phase

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